表格

begin{table}[H]
    \centering
    \caption{偶极子天线的相位差与能量差}
    \begin{tabular}{l|ll}
    \hline
    第二个偶极子天线长度&S21 Gain&S21 Phase \\
    \hline
    70mm& -10.56dB & -15.52° \\
    60mm& -7.47dB & 10.26° \\
    50mm& -12.89dB & 78.93° \\
    40mm& -21.85dB & 109.38° \\
    \hline
    \end{tabular}
\end{table}

子图

begin{figure}[htbp]
    \centering
    \begin{minipage}{0.49\linewidth}
        \centering
        \includegraphics[width=0.9\linewidth]{-2.png}
    \end{minipage}
    \begin{minipage}{0.49\linewidth}
        \centering
        \includegraphics[width=0.9\linewidth]{2023-06-15-16-51-00.png}
    \end{minipage}
    %\qquad
    %让图片换行，

    \begin{minipage}{0.49\linewidth}
        \centering
        \includegraphics[width=0.9\linewidth]{2023-06-15-16-51-00.png}
    \end{minipage}
    \begin{minipage}{0.49\linewidth}
        \centering
        \includegraphics[width=0.9\linewidth]{2023-06-15-16-51-00.png}
    \end{minipage}
    \caption{mother of chutian}
\end{figure}